1. Field of the Invention
The present invention relates to the use of ultrasound in nondestructive evaluation, and particularly to the use of ultrasound in a field instrument for measuring texture, stress, and related material properties to infer properties relating to formability in sheet or plate having crystalline structure.
2. Problems in the Art
Nondestructive evaluation (NDE) is of great and increasing importance in present day technological environments. Prominent NDE systems utilizing ultrasound, x-ray diffraction and magnetic evaluation, among others, enable analysis of a wide variety of materials relatively efficiently and economically. Obviously, NDE has the primary advantage of avoiding destructively sampling the material being analyzed.
The advantages of NDE are widely known. Developments continue with regard to all areas of NDE.
Ultrasonic methods of NDE have particular advantages over other types of NDE under recent circumstances. Recent advances have broadened the applicability of ultrasonic NDE and the accuracy of ultrasonic NDE.
While the advantages and advances with regard to ultrasonic NDE have been realized in laboratory settings, there is still a real need in the art for methods and instruments which can be utilized directly in the manufacturing processes and environments for the materials being analyzed, and to be able to be used in a variety of locations and situations for evaluating parts and materials during their life span.
There is a very real need for an accurate, fast, and reliable system to measure and analyze materials nondestructively, in process or at an easily accessible location, that is, in the field.
For example, in the manufacture of metal sheet or plate, the manufacturing process produces a texture (or preferred grain orientation) in the sheet or plate because of the crystalline structure of metal. This texture, as is well known in the art, affects the material properties and characteristics of the sheet or plate. It is therefore valuable first to know what type of texture the sheet or plate has, and second, to be able to use that information to infer properties relating to the formability of the plate or sheet.
By way of another example, it is valuable and indeed critical to be able to analyze the integrity of in-use parts and materials such as airplane wings. Detection of stresses within the wing can enable the wing to be removed or repaired before failure.
While there are many different methods and apparatus which are currently being used or have attempted to be used to meet these needs, none has successfully achieved all of these needs in one field instrument and method. Furthermore, in ultrasonic NDE, there are many areas where accuracy and reliability of the ultrasonic investigation, and the results derived from it, are significant.
There is therefore a real need in the art for a field instrument for ultrasonic measurement of material properties in plate or sheet of crystalline structure which is nondestructive, is adaptable to on-line or in process environments, is easily movable and usable at a variety of locations, is easy to operate, accurate, and reliable, and can be used to measure a variety of material properties for a variety of materials.
In real world situations this means that such a means and method must be usable in environments of wide ranging temperatures, such as in on-line manufacturing of metal plate where very high temperatures exist. It also must be of a size which can be practically portable, both as to the ultrasonic transducers and the components operating the transducers and deriving results from the transducers. Moreover, it must be easily operable and durable.
It is also important to understand that a need exists for such an instrument which can accurately measure as many material properties as possible, for as many different types of materials as possible. There is a need, therefore, for investigative transducers which are adaptable to a variety of situations and materials, a need for the ability to measure a variety of material properties such as texture and stress, and a need to analyze a variety of types of materials, for example, ferrous materials and nonferrous materials.
To enable such flexibility, the control and processing equipment must be adaptable to that variety, and also must solve or compensate for problems and potential error influences that can occur.
For example, ultrasonic transducers can experience problems with lift-off in settings where there is not the ability for precise laboratory controls. Compensation and control of any effect to the processing of the ultrasonic signals must be compensated for. Additionally, the instrument must be flexible to allow interchangeability of components for various situations. Ferrous materials, for example, may require different types of transducers than nonferrous materials.
Finally, the instrument must be accurate to within acceptable margins of error. Processing of the signals obtained by the transducers must therefore be accomplished to meet this error margin.
It is therefore a principal object of the present invention to provide a field instrument means and method for ultrasonic measurement of texture, stress and related material properties to infer properties relating to formability in crystalline sheet or plate which improves over or solves the problems and deficiencies in the art.
A further object of the present invention is to provide a means and method as above described which allows efficient and accurate implementation of ultrasonic nondestructive evaluation.
A further object of the present invention is to provide a means and method as above described which allows nondestructive measurement of a variety of material properties including texture and stress accurately and reliably.
Another object of the present invention is to provide a means and method as above described which effectively and flexibly allows nondestructive ultrasonic evaluation of a variety of materials in process or on location.
Another object of the present invention is to provide a means and method as above described which is flexible in its adaptability and adjustability for different materials and different material properties.
A still further object of the present invention is to provide a means and method as above described which can nondestructively evaluate materials which are either stationary or moving at unknown speeds.
Another object of the present invention is to provide a means and method as above described which can facilitate process control of materials or monitor residual or applied stress during the life cycle of the material.
Another object of the present invention is to provide a means and method as above described which can function accurately and reliably in a variety of different environments and locations.
A still further object of the present invention is to provide a means and method as above described which can quickly process ultrasonic transducer signals and produce accurate and reliable results regarding material properties such as formability parameters of the material investigated.
These and other objects, features, and advantages of the present invention will become more apparent with reference to the accompanying specification and claims.